RobY Posted December 23, 2004 Share Posted December 23, 2004 electro-pneumatically 'active' differentials at the back, front and centre Link to comment Share on other sites More sharing options...
ADirtyLegacy Posted December 23, 2004 Share Posted December 23, 2004 ya know....if you sit on your ass long enough and don't advance yourself and your designs, you will eventually be surpassed and embarassed and playing catch up..... Kenda Link to comment Share on other sites More sharing options...
lemming Posted December 23, 2004 Share Posted December 23, 2004 it's not clear to me that a FWD-based and derived car then post-engineered to have AWD is "perfection". it's one way to achieve the benefits of AWD, but perfection would be a car with AWD integrated into the design a priori, in lockstep with the chassis designers. it means that weight is usually lower and the design is simpler which also usually means lighter. electronic-brake differential systems as are now found in bmw, audi quattro (no longer mechanical LSDs), porsche (carrera 4s), vw, volvo and now acura are effective but far from perfection. if they were, it would be found in rally cars. racing always finds the most parsimonious and effective answer. Link to comment Share on other sites More sharing options...
IwannaSportSedan Posted December 23, 2004 Share Posted December 23, 2004 What really gets me is the disposable nature of a lot of the new drivetrain technology. When it breaks, replace it. Cars aren't under warranty forever, and that gets damn expensive. I am not sure about the SH-AWD system's longevity, or repairability, but usually electronics are a replace-only prospect. Mechanical systems tend to be more robust and repairable if designed and built well, than an electro-mechanical system, or all electrical system. Do the SH-AWD's electronically controlled clutches wear out? Perhaps I am wrong, but I have had to replace more electrical components on my cars than mechanical, by a pretty good margin. I have to wholeheartedly agree with lemming about AWD being "designed-in" rather than added to a pre-existing 2wd drivetrain seems like the way to go. That is why I don't view the Ford/Mazda/Volvo/Jag Xtype/VW/and on and on Haldex system as an equal competitor to Subaru's symmetric AWD. Sure it helps, but not all AWD is created equal. I am sure it can be made to work well, but using clutches, or yet brakes to control AWD drivetrain management seems overly complex to me, and combining separate systems. It seems overly complex when spider gears and planetary gears can be used to have the drivetrain manage itself using it's own torque, and leave the brakes to slow the car, and have only one pedal-activated clutch to eventually replace. It is interesting that the WRC cars use 3 active diffs. Good info to know. On a street car, I would think 3 torque sensing diffs (no real huge need to manage or worry about adjusting diffs manually for the street) that are "automatic" for the torque split, and not slip-based, for the most part seem like the best choice for a car like the Legacy, if cost is not considered. I am sure the Viscous center and rear LSDs are not too shabby, either. Link to comment Share on other sites More sharing options...
Drift Monkey Posted December 23, 2004 Share Posted December 23, 2004 [quote name='lemming']it's not clear to me that a FWD-based and derived car then post-engineered to have AWD is "perfection". it's one way to achieve the benefits of AWD, but perfection would be a car with AWD integrated into the design a priori, in lockstep with the chassis designers. it means that weight is usually lower and the design is simpler which also usually means lighter. electronic-brake differential systems as are now found in bmw, audi quattro (no longer mechanical LSDs), porsche (carrera 4s), vw, volvo and now acura are effective but far from perfection. if they were, it would be found in rally cars. racing always finds the most parsimonious and effective answer.[/QUOTE] AFAIK Audi still uses Torsen diffs for their Quattro and a clutch system for Haldex systems. The center diffs however are now electronic. Link to comment Share on other sites More sharing options...
RobY Posted December 23, 2004 Share Posted December 23, 2004 If im not mistaken the quattro just consists of a center torsen and front and rear "electronic" brakeforce diffs. Quattro isnt what it used to be. In fact it quite handily crappied itself out due to cost cutting. Link to comment Share on other sites More sharing options...
Drift Monkey Posted December 23, 2004 Share Posted December 23, 2004 [quote name='RobY']If im not mistaken the quattro just consists of a center torsen and front and rear "electronic" brakeforce diffs. Quattro isnt what it used to be. In fact it quite handily crappied itself out due to cost cutting.[/QUOTE] [url]http://www.audiusa.com/lexicon/0,0,categoryId-4_,00.html#146[/url] [url]http://www.audiusa.com/quattro/0,,status-P_countrycode-1_usageId-83_,00.html[/url] Link to comment Share on other sites More sharing options...
RobY Posted December 23, 2004 Share Posted December 23, 2004 Sounds like a center torsen and electronic brakeforce diff to me... Trust me I quite handily whipped my buddy's 2003 A4 while his front and rear calipers were clapping back and forth in the snow... Link to comment Share on other sites More sharing options...
Drift Monkey Posted December 23, 2004 Share Posted December 23, 2004 [quote name='RobY']Sounds like a center torsen and electronic brakeforce diff to me...[/QUOTE] 'Electronic Differential Lock' Link to comment Share on other sites More sharing options...
rao Posted December 23, 2004 Share Posted December 23, 2004 The Audi system is annoying, it made me mental (well more mental). give me a real limited slip diff any day over the half-baked "let's use the brakes to shift the power to the other side as long as the fcar is going less than 25" any day. Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
RobY Posted December 23, 2004 Share Posted December 23, 2004 Yeah your brake locks the other wheel so that it dosent spin freely :D Link to comment Share on other sites More sharing options...
rao Posted December 23, 2004 Share Posted December 23, 2004 :lol: Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.